Automatic releasable lock



Aug. 15, 1944.` T, l... RQBERTS AUTOMATIC RELEASABLE LOCK Filed-April20, 1942 FIG. 4

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Swim/Wto@ 52 THOMAS L. ROBERTS am@ s.

, 5 www Patented Aug. 15, 1944 UNITEDA STATE AUToMA'rIC RELEASABLE Loox,Thomas L. Rberts, st; Paul, Minn'. Application Apriiz, 1942, serial No.489,781

A claims. (01.292-78) My invention relates to automatic releasable locksand has for its object to provide a locking ly held in position. Yet, ifthis holding does not readily yield under impact of an explosion withinthe oven there may be serious Wrecking of and injury to the oven'itselfand even the building and other devices surrounding it.

It is a principal object of my invention therefore, to provide anautomatic locking device, which, While it will hold the oven door tightand very secure under normal conditions, yet can yield to permitswinging open of the door when excessive pressure develops from withinfrom any cause, such, for example, as an explosion within the oven.

A further object of my invention is the provision of a lock membermounted to swing on a pivot and having angularly disposed contactsurfaces such that when the door is swung to closing position one ofthese surfaces will .be engaged by a lxedly positioned catclrmember insuch manner that such engaged surfaces will be moved out of its line ofmovement during closing and the other surfaces will be moved behind thecatch member to engage it and hold it in locking position, together withmeans for exerting spring pressure on the lock member to hold it ineither of its adjusted positions.

It is a further object ofA my invention to form a lock member of amultiplicity of plates rigidly united together and to have some of theseplates extend rearwardly to form spaced members which may be bent towardeach other to form a rough socket and provide a member having a partadapted to enter said socket which may be turned and at the same timehas means for holding it in one xed position.

It is a further object of my invention to provide in connection with theaforesaid turnable member a strong spring surrounding it and a followerthreaded upon said member so as to engage said spring, said followerbeing mounted in a channel with straight edged walls, the followerhaving corresponding walls adapted to engage the channel walls andprevent it from turning.

The full objects and advantages of my inven-Y tion will appear inconnection with the detailed description now given in the'appendedspecification, and the novel features by which the aforesaidadvantageous results are obtained are particularly pointed out in theclaims.

In the drawing illustrating an application of my invention in one form-Fig. 1 is a plan view of the lock casing in which my invention may behoused.

Fig. 2 is a side elevation of the same.

Fig. 3 is a sectional elevation View taken on line 3-3 of Fig. 1.

' Fig. 4 is a transverse sectional plan view taken on line 4-4 of Fig.3.

Fig. '5 is an enlarged sectional fragmentary View taken on line 5-5 ofFig. 3.

Fig. 6 is a full face plan View of the lock member dissociated from theother elements of the invention,

As illustrated, a member I0 is adapted to be bolted to a xed oven wallby suitable bolt members passing through bolt holes II and I2. A secondmember I3 embodies side walls I4 and I5, Fig. 4, spaced apart and havinginner plane walls I6 and I'I, which inner walls may be parallel as shownin Fig. 4. The member I3 also has a thickened top Wall I8. Between theside walls I4 and I5 and enclosed by the top Wall I8 is a lock chamberI9 which is open at its face 2U as indicated in Figs. 4 and 5.

The member I0 fast on the oven wall is provided with a thick Wallprojecting portion 2|, Figs. 1 and 3, having therein a transverse cavity22, Fig.3, which is open at its ends as indicated at 23 and 24, andwhichalso is open along its extent fronting member I3 as indicated at25, Fig. 3. When the parts are attached to a fixed furnace wall and awallA of the oven door is in closed locking position, as in Fig. 3, theopen end 20 of chamber I9 and the open end 25 of chamber 22 will be injuxtaposed position so as to form one continuous substantially enclosedchamber.

Extending between the sides of the wall 2| is a strong shaft or pin 26upon which is mounted a roller 2l. This roller is adapted to be engagedby one or the other of a pair of faces 28 and 29 on a lock member 30;This lock member is formed of a multiplicity of sheet metal plates 3|,32 and 33, as clearly shown in Figs. 4 and 5'. These metal plates aresecurely held togetherby suitable means, preferably by strong rivets 34and 35, Fig. 3, extending through openings 36 and 31, Fig. 6. Any numberof such plates may ing into a'threaded opening 42 across shaft 4| is aset screw 44 which has its head 43 of such diameter as just to t betweenthe walls 45 and 45 of the cut-out space 39. By meansof Athis set screwthe rocking lock member 30 is held in a fixed position both axially andlongitudinally on the shaft 4|.

The plates 3| and 32 are turned toward eachf other as indicated at 41and 48 of Figs. 4 and 5,

and the plates 33 are semi-circularly cut out, as indicated at 40 ofFig. 3. taken. in conjunction with the turnedin'portions 38 o'f plates3| and 32 produces a flat-sided socket 50, Fign'. In this socket' 50 isa head 5| fast on aV bolt member 52 threaded at 53 adjacent the head1`5|, and formed with a screw driver slot 54 on its outer end, Fig. 3..The head is spherical except,"as best shown in Fig. .'5, where it isprovided with oppositely-disposed flat faces 55 and-55. VThe rounded endof head 5| tthrusts A against the curved bottom of cavity 50, as shownat 5l in Fig. 4, and the outer end of bolt member 52 protrudes throughan opening 58 in the rear end wall 59 enclosing chamber I9 of lockmember i3.

On the threaded portion v53 of bolt member 52 is threaded a followernut6i), the walls of which are in close proximity with walls I5 and |'|Y ofthe chamber |9 in'main lock casing I3. The head 5| in the cavity 5E) isrestrained from pulling out by reason of the fact the oppositeVfaces-.of bent-in'po`rtions 33 of plates v3| and 32 forming the sidewalls ofl socket 55 prevent it; It :follows that when the bolt 52 is`turned inleitherv direction. the follower nut 6E! will be caused totravel along the bolt either to put more or less compression on a heavyspring 5| surrounding bolt 52 and extending between the;

inner wall of end 59 and follower 53, as shown in Fig. 3. i

Although the bolt 52 is Ythus permitted to turn for adjusting thecompression of spring "5i, which is absolutely essential for :thepurpose of my invention, the bolt must not be free to turn exceptingwhen itis intended to be turned-that is, the closing and opening of thedoor and the consequent swinging of lock member 3|) upon its supportingbolt 4|) must not automatically turn or vpermit the turning of the bolt52, which, be cause the spring 5| constantly urges the follower 60toward the head 5|, would normally tend to move the follower toward thehead to loosen the hold of the lock nut; This might continue to a pointwhere the door would not remain closed against normal internal pressurein the oven.

Thearrangement above described ofthe flattened head 5| `in the socket 50enables the bolt 52 to be turnedto any desired degree, and when theturning is finished the faces 55 and56 of the head 5| will snap againstthe faces of the turned-in portions 38 of plates 3l and 32 and hold thebolt against turning.

This cut-out portion The fact that the plates 3| and 32 and the bentextensions 38 thereof are of sheet steel with a normal ability to swingor yield is one of the things which makes the above operation possi- 5ble.

I claim:

1. A releasable lock comprising a swinging lockmember formed of a seriesof sheet metal plates shaped and secured together to form a sockethaving a plane face, a spring-pressed member having a head in saidsocket engaged'by said face with a yielding pressure, means for forciblyrotating said member against said pressure, and means on the headengageable with said face in one position of rotation of the head tohold the spring-pressed member against turning in the normal operationof the lock.

2.' A releasable lock comprising a swinging lock member formed of aseries of sheet metal plates shaped and secured together to form asocket having a pair of plane faces, a rotatable vspringpressed memberhaving a Yhead insaid socket, and means on the head for engaging thewalls of the socket normally to hold the member against turning.

3. A releasable lock comprising a swinging lock member formed of aseries of sheetvmetal plates shaped and secured together to form asocket having a pair of oppositely disposed plane Vfaces, aspring-pressed member having a head in said socket located between andengaged by said v faces with a yielding pressure, means for forciblyrotating said member against said pressure,` and means on the headengageable with saidffaoes 3Min one position of rotation of the head tohold` the spring-pressed member againstV turning in the normal operationof the lock. `v

4. A releasable lock comprising a swinging lock member formed 0f aseries of sheet` metal plates Vligjshaped and secured together to form asocket lhaving a pair of oppositely disposed plane faces, aspring-pressed member having a head in said socket located between andengaged by said faces with a yielding pressure, means for forciblyfro--lfftatin-g said member against said pressure, and a pair of flat faceson opposite sides of the head, each engageable with one of said faces inone position of rotation of the head to hold the spring-pressed memberagainst turning in the tnormal operation of the lock.

5. A releasable lock comprising a lock casing having a parallel-walledchamber, a lock member having two contact faces, means mounting saidlock member to swing between the walls of said schamber, a socket onsaid lock member having- @0r-otherwise rotatable by force within saidsocket,

a follower on said threaded member engageable with the walls of thechamber and adapted toy swing with the lock member past dead center ofthe point of pivot of the lock member to hold 'the same in fixedposition on either side of said pivot, a spring engaging said followerto cause the same through the threaded bolt in the socket to exert forceupon the follower, said follower and the faces on said head permittingsaid swing- .ing motion within the parallel-walled chamber,

THOMAS L. ROBERTS.

